Method and apparatus for usable beam current and brightness in schottky thermal field emission (tfe)

A non-transitory computer readable medium having instructions stored therein that, when executed by one or more processors, cause the one or more processors to perform a method to determine Schottky thermal field emission (TFE) usable current and brightness of a Schottky TFE source, the method comprising:

• acquiring and storing to a memory a Schottky TFE emission image in a digital format;
• normalizing and summing pixel data values of the acquired and stored Schottky TFE emission image;
• assigning a pixel current based on the normalized and summed pixel data values and a beam current, wherein the beam current comprises a central beam component and an outer beam component;
• and
• determining Schottky TFE usable current and brightness based on the assigned pixel current and usable current criteria,
• wherein the assigning of the pixel current based on the normalized and summed pixel values and the beam current further comprises assigning each pixel a value proportional to each pixel's intensity, dividing beam current by the sum of normalized pixel values, and assigning resulting fraction of the beam current to each pixel.

A system for determining Schottky thermal field emission (TFE) usable current and brightness of a Schottky TFE source, the system comprising:

• one or more processors, configured to:
• acquire and store in a memory a Schottky TFE emission image in a digital format;
• and
• determine Schottky TFE usable beam current and brightness for the based on experimentally developed algorithms that utilize usable current criteria and usable emission current density, wherein the usable current criteria are generated based on properties of central beam component and outer beam component of Schottky TFE beam current.